Which two methods of data collection require other data sources for valid interpretation?

The correct answer identifies observations and surveys as methods of data collection that necessitate additional data sources for valid interpretation. Observations can provide valuable insights into behaviors or activities, but without supplementary context or data from other sources (such as interviews, background information, or quantitative data), the meaning of what is observed may be incomplete or misinterpreted. For example, observing a group of people in a public place might reveal patterns, but without understanding the context or motivations behind those behaviors, the interpretation may lack depth or accuracy.

Similarly, surveys gather responses from individuals regarding their opinions, experiences, or feelings, yet the data derived from surveys may require merging with qualitative data, like interviews or case studies, to ensure a thorough understanding of the reasons behind those responses. The attitudes indicated in survey responses may not fully capture the nuances of individuals' experiences without additional qualitative information.

In contrast, methods such as command records and interviews or the combination of interviews and observations do not inherently require supplementary sources for valid interpretation. Command records provide factual data that can stand on their own, while interviews, although they benefit from context, can still yield significant insights independently depending on the depth and quality of the questions and answers involved.